In order to form color photographic images, it is well known that an exposed -photographic light-sensitive material having light-sensitive layers containing photographic couplers for the three colors, yellow, magenta and cyan, respectively, is subjected to color development processing using a color developing agent. In this processing, a colored dye is formed upon a coupling reaction of a coupler with an oxidation product of an aromatic primary amine. It is preferred that the couplers have a coupling rate which is as fast as possible so as to provide high color density within a short developing time.
On the other hand, the color photographic images formed are required to show good preservability under various conditions. In order to satisfy this requirement, it is of importance that dyes formed with different hues show a slow color fading or discoloring rate and that the dyes show a discoloring rate as uniformly as possible over the total image density region so as to not make the color balance of the remaining dye image unbalanced.
With conventional light-sensitive materials, particularly color papers, cyan dye images are seriously deteriorated by long-time dark fading due to the influence of humidity and heat and, hence, they are liable to undergo changes in their color balance, and there is a strong desire in the art to improve this fault Cyan dyes with good dark fading resistance, conventionally, show poor hue and are liable to fade and disappear under light. Thus a novel combination of couplers has been demanded, because there has been a fairly marked reciprocal tendency therebetween.
In order to partly solve this problem, there have so far been proposed specific combinations of various couplers Some examples are given in, for example, Japanese Patent Publication No. 7344/77, Japanese Patent Application (OPI) Nos. 200037/82, 57238/84, 160143/84 and 205446/85 (the term "OPI" as used herein means an "unexamined published application). However, these combinations still fail to totally remove all disadvantages in that only insufficient color forming properties are obtained; the dyes formed have so poor a hue that color reproduction is adversely affected; the color balance of the final dye image is changed due to deterioration by, particularly, heat or light; and the cyan hue temporarily disappears under light.
Recently, demands on silver halide photographic materials have become much stricter in the art. For example, with respect to color paper, it has been strongly desired to get high sensitivity in order to reduce the time for printing and to achieve uniformity, that is, to minimize differences in sensitivity due to change of properties with the lapse of time or differences in sensitivity between lots of color paper to increase the yield of useful prints.
Various investigations have been made in order to increase the spectral sensitivity of -photographic light-sensitive materials. For instance, the art has searched for sensitizing dyes having good spectral sensitizing efficiency. Also, supersensitization has been attempted. Specifically, a method for increasing the spectral sensitizing efficiency by a combination of some kinds of specific sensitizing dyes and methods using a combination of specific compounds and sensitizing dyes are as described in T.H. James, The Theory of the Photographic Process, Fourth Edition, pages 259 to 265, Macmillan Co., N.Y.
Further, as is well known in the art, there is another method for increasing spectral sensitivity where the inherent sensitivity of silver halide per se is increased by means of, for example, using silver halide grains of large size or appropriately selecting the method of chemical sensitization. However, although these methods are effective as far as an increase in spectral sensitivity is concerned, they are accompanied with some adverse effects on other -photographic properties, for example, a severe increase in fog, a deterioration in preservability, and an increase in remaining color due to sensitizing dyes. Thus they are still insufficient for practical purposes.
With silver halide color -photographic materials, it has been desired to develop a technique which can simultaneously overcome the degradation problems with cyan dye images due to the influence of light, heat and humidity with no reciprocal tendency among the degradation problems remaining, in order to achieve good preservability of color photographic images formed under various conditions. Techniques which partially address these problems result in various disadvantages in color forming property, the color hue of dyes formed, sensitivity and uniformity, etc., as discussed above, and thus there is today no practical means to solve the above problems Accordingly, it has become very important to provide a means to totally solve the above problems.